In any enclosed system containing a flowing fluid, such as a piping system, there is frequently a need to make directional changes in the fluid flow. Typically, standard piping elbows, also referred to as bends, are used. However, circumstances frequently exist that impose constraints and preclude the use of standard piping elbows. These circumstances include the conveying of high temperature fluids, corrosive fluid streams, or abrasive fluid streams such as those that are particulate-laden fluid streams. When these conditions exist, a typical solution to changing the fluid flow direction often involves using larger size (that is, greater diameter) piping elements lined with an appropriate refractory, corrosion-resistant, or abrasion-resistant lining.
An increase in the piping diameter requires an accompanying increase in the turning radius of any needed bends. The increase in turning radius in turn increases the space requirements for installing an elbow or bend needed to make a change in the fluid flow direction. Utilizing an elbow or bend with too small of a turning radius typically causes an undesirable pressure loss.
As related in a commonly-assigned application filed concurrent with the present application, the inventors have addressed one or more of the above-mentioned deficiencies in the prior art by providing a piping elbow capable of facilitating a fluid flow direction change in a smaller space than conventional piping elbows, without causing the larger pressure losses found when using conventional elbows in the equivalent space. These piping elbows comprise a substantially-cylindrical body having a first end, a second end, and a substantially-constant inside diameter; a tangential inlet attached to the body near the first end of the body and having an inside diameter smaller than the inside diameter of the body; and a tangential outlet attached to the body near the second end of the body and having an inside diameter smaller than the inside diameter of the body. Typically, fluid flows linearly through the tangential inlet and enters the body. Inside the body, linear motion of the fluid is converted into a rotational or spiral motion. The fluid in the body continues its spiral motion as it also moves axially through the body toward the tangential outlet. The fluid exits the body through the tangential outlet. Upon exiting through the tangential outlet, rotational or spiral motion of the fluid in the body is converted back into linear motion.
In a preferred embodiment, the piping elbows comprise two substantially-identical components attached to each other. In another preferred embodiment, the two substantially-identical components are removably attached to each other so that the tangential inlet/outlet on the first component can be oriented at any desired angle with respect to the tangential inlet/outlet on the second component.
The present application concerns a liner which is especially adapted for use with the above-described piping elbows, for example, in redirecting flows of high temperature and/or highly abrasive fluids, as well as methods of making the liner. In one embodiment, liners according to the present invention comprise a body liner, a tangential inlet liner, and a tangential outlet liner. In one preferred embodiment, the tangential inlet liner and the tangential outlet liner are each removably inserted into a cavity in the body liner. In another embodiment, the body section liner comprises two substantially-identical body section liners. A method of making the liner in its preferred embodiment comprises providing a first substantially cylindrical structure having an inside surface and an inside diameter, providing second and third substantially cylindrical structures which each have a first end, an inside diameter smaller than the inside diameter of the first structure and an outside diameter, creating two cavities in the first structure which have a diameter equal to or greater than the outside diameter of the corresponding second and third structures, shaping the first ends of the second and third structures to be substantially identical to the shapes of the created cavities in the first structure, and inserting the shaped first ends of the second and third structures into the matching cavities in the first structure.